Aim: The purpose of this study was to explore sexual dimorphism in the distance between mental foramen to lower border of mandible in Chinese patients attending Faculty of Dentistry, MMMC and to derive a discriminant equation for determining sex using the data obtained. Material and method: The archived digital orthopantomograms at the institutional database were screened and 140 radiographs were selected based on inclusion and exclusion criteria for analysis of mental foramen. Measurements between the three reference points (superior and inferior border of mental foramen and lower border of mandible) were made using Romexis software (Version: 3.0.1.R) measuring and drawing tools. The data obtained were tabulated and subjected to discriminant function analysis. Results: Distance between mental foramen to lower border of mandible (both Right and Left S-L and I-L) were significantly higher in male than female at the level of P